Half to dorr b



(No Model.) 2 Sheets-Sheet 1.

I. A. BURNHAM. STEAM ENGINE No. 644,476. Patented Aug. 13,1895.

INVENTOH Jay-Mt A TTORNEYJ (No Model SheetsSheet 2.

F. A. BURNHAM.

' STEAM ENGINE.

INVENTOH A Tron/v5 YS UNITED STATES.

PATENT OFFICE.

FRANK A. B URNHAM, OF BATTLE CREEK, MICHIGAN, ASSIGNOR OF ONE- HALF TO DORRB. BURNHAM, OF SAME PLACE.

STEAM-ENGINE.

SPECIFICATION forming part of Letters Patent N 0. 544,476, dated August 13, 1895. Application filed October 30, 1894-.- Serial No. 527,438- (No model.)

To all whom it'may concern.-

Be it known that I, FRANK A. BURNHAM, a citizen of the United States, residing at Battle Creek, in the county of Calhoun and State of Michigan, have invented certain new and useful Improvements in Steam-Engines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in steam-engines, and particularly to improvements in the mode and means of automatically operating the main valve of the engine.

The invention is applied to direct-acting steam-pumps, as shown in my Patent No. 519,857, dated May 15, 1894, but it'is equally applicable to all reciprocating-piston engines.

The invention consists in the combination,

, in an engine of the character above indicated,

of a valve-chest and cylinder, having independent passages leading from steam-chambers in the ends of said chest to exhaust, and steam-actuated valves or gates arranged in or across said passages.

It also consists in other combinations, hereinafter described and claimed.

In the drawings, Figure l is a central longitudinal section through the steamchest and cylinder of an engine, showing the arrangement of my improvements in dotted lines- Fig. 2 is a plan of the cylinder adjacent to the valve-chest. Fig. 3 is a cross-section on the line 3 3 of Fig. 1. Fig. 4: is a longitudinal section on the lines 4ofFig. 3.

A is the cylinder; B, the piston; O, the valve-chest, and D the valve of an ordinary. piston engine. The cylinder A is provided with the usual steam ports, passages, and cavities, the inlet-passages being seen at a and a, the exhaust-passages at b, and the cavities at 0 and 0. The piston is provided with the usual packing-rings. The valve-chest O is attached vto the cylinder by bolts in a wellknown way and contains a piston for operating the main valve D. This piston is provided with heads F and F at opposite ends thereof, which fit in chambers G G in the valve-chest, and these heads have constrictedsteam-ports d at through them.

The stem connecting the two heads carries collars c 0, between which the main valve is held and its movement controlled.

H is the induction pipe for conducting steam from generator to steam-space I of the steam-chest. Leading from the outer ends of thechambers G and G to exhaust b are passages g and g to intermittently permit the escape of steam from the chambers behind one head of the valve-operating piston.

J and J are piston valves or gates having annular grooves f f arranged so that the grooves will alternately register with exhaustpassages g g. These pistons or gates are arranged at one side of the cylinder in such position that the main engine-piston alternately passes them just before the completion of its stroke. j Leading from the main cylinder to one end of these pockets, in which the pistons or gates J J are fitted, are ports it It, and leading from the extremities of the main cylinder to the other end of the pockets in which such pistons or gates are fitted are also ports P P To avoid having the grooves ff closed at any time I make branches m m in the exhaust-passages g g. This provides for ex hausting the steam from the grooves. The valve D has the usual cavities n n. v

In operation, the main engine-piston having just completed its stroke to the right, steam passes from the main cylinder through port is and raises valve J and brings the groove f coincident with the exhaust-passage g and exhausts the steam in chambers G faster than 'it can flow through small portal, and the piston-head F, being exposed to full steam-pressure, is carried to the right and carries the main valve D with it. The cavity a in the valve now makes communication with steamport a and exhaust-port b and exhausts the steam from main cylinder A. The cavity at now communicates with the steam-port a and the cavity 0' in the cylinder-face, and steam is admitted to the cylinder through port a. Steam will now flow through passage P to the top of the valve or gate J and force it down and close the exhausts through g. The valve-driving piston is now balanced under an equal pressure at both ends.

Having described my invention, what I claim as new is- 1. In a steam engine the combination of a valve operating piston, having recessed heads and constricted ports, a steam chest having independent exhaust passages leading from end chambers thereof to main exhaust and steam actuated gates or valves arranged across the passages substantially as described.

2. In a steam engine the combination of a steam chest having independent passages from end chambers of said chest to main exhaust, gates or valves in said passages and passages from the main cylinder leading to opposite ends of the valves substantially as described.

3. In a steam engine the combination of a steam cylinder having valve or gate pockets arranged at one side of the main piston open- FRANK A. BURNI-IAM. Witnesses:

I. J. MOUSER, J. F. SHAUL. 

